Ebook: Hydraulic and Civil Engineering Technology VIII
All of us are dependent on a built environment constructed and maintained by civil and hydraulic engineers, and for those working in these fields, keeping up to date with the latest technological developments is vital for the safe and efficient design and operation of this infrastructure.
This book presents the proceedings of HCET 2023, the 8th International Technical Conference on Frontiers of Hydraulic and Civil Engineering Technology, held from 25-27 September 2023 in Wuhan, China. HCET is an international conference which aims to enhance the development of hydraulic and civil engineering in China, with a focus on high-end, intelligent and green technologies. It seeks to do this by consolidating global wisdom and achievements and providing scientific support. HCET also offers an excellent opportunity for scientists, researchers and engineers from around the world to exchange their findings and discuss developments, establishing a basis for national and international collaboration. A total of 316 contributions were received for the 2023 edition, of which 187 were ultimately accepted after a rigorous review process and checks for quality and plagiarism. Topics covered include the research and development of concrete structure design and analysis; structural mechanics and structural engineering; building and future materials; hydraulic engineering; geological exploration and earthquake engineering; building technology; urban planning; road, bridge and traffic engineering; energy infrastructure; environmental engineering and advanced engineering technologies, and interdisciplinary sciences and applications.
Covering a wide range of subjects related to hydraulic engineering and civil engineering technology and associated transdisciplinary sciences, the book will be of interest to all those working in the field.
The 8th International Technical Conference on Frontiers of Hydraulic and Civil Engineering Technology (HCET 2023) was held in Wuhan from 25–27 September, 2023. HCET23 is organized by the China Construction Seventh Engineering Division Corp Ltd, Southwest Jiaotong University, China, China University of Geosciences (Wuhan) and Henan Polytechnic University, China, and co-sponsored by China Communications Construction Group Co. Ltd, China Railway Major Bridge Engineering Group Co. Ltd (MBEC), Toronto Metropolitan University, Canada, and Northwestern University, USA.
HCET is a high-end, international conference in the field of hydraulic engineering, civil engineering technology and transdisciplinary sciences, established by CUG (China University of Geosciences), Wuhan. The conference aims to enhance the development of hydraulic and civil engineering technology in China, and orientate manufacturing towards high-end, intelligent and green. It seeks to consolidate global wisdom and achievements and contribute scientific support. HCET provides a unique platform and an excellent opportunity for young scientists, researchers and engineers from around the world to exchange their findings and discuss developments, and to establish a basis for collaboration at both a national and international level.
This volume presents full-length research papers from international contributors. This year, we received over 316 contributions, all of which were subjected to a rigorous peer-review process commensurate with their track, with each paper being reviewed by a minimum of two experts. After review and checks for quality and plagiarism, 187 papers from both Chinese and international scholars were ultimately accepted for publication. These contributions focus on the research and development of concrete-structure design and analysis, structural mechanics and structural engineering, building and future materials, hydraulic engineering, geological-exploration and earthquake engineering, building technology, urban planning, road, bridge and traffic engineering, energy infrastructure, environmental-engineering and advanced-engineering technologies, and interdisciplinary sciences and applications.
We would like to take this opportunity to express our appreciation to the keynote speakers: Prof. Zdeněk P. Bažant, National Academy of Sciences, National Academy of Engineering, Northwestern University, USA; Prof. Xudong Qian, National University of Singapore, Singapore; Prof. Bin Xu, Huaqiao University, China; Prof. Xiaonan Tang, Xi’an Jiaotong-Liverpool University, China; Prof. Baoguo Han, Dalian University of Technology, China; Prof. Jianhui Yang, Henan Polytechnic University, China. We also extend our sincere thanks to all HCET international reviewers and members for their contributions and commitment in putting together a program of presentations, and to all those participants who contributed their latest researches to the HCET2023 proceedings.
Looking forward to seeing you at HCET2024, in Chengdu, China!
Yanjun Qiu, Southwest Jiaotong University, China
Wanqing Lu, China Construction Seventh Engineering Division. Corp. Ltd., China
Jianhui Yang, Henan Polytechnic University, China
Said Easa, Toronto Metropolitan University, Canada
The effect of roof pitch angle on the buckling capacity of cylindrical shells when subjected to uniform external pressure was investigated numerically. Thirty-six cylindrical shells were modelled in ABAQUS CAE, with the modelled shells having various length-to-radius ratios of L/R = 0.5, 1, 2, and 4, various radius-to-thickness ratios R/T = 300, 500, and 1000, and various roof pitch angles of θ = 0, 15, and 30. The buckling mode and buckling capacity of the cylindrical shells were obtained. The results showed that the buckling capacity of the shells increased with decreasing the R/T and L/R ratios and increasing the roof pitch angle. Additionally, the results showed that when the cylindrical shells had R/T = 300 and L/R = 0.5, 1, and 2, a significant shell’s structural gain was obtained with minimum use of extra materials by increasing the roof pitch angle.
Lead core rubber bearings are among the commonly used devices for seismic isolation of buildings and structures. They are a part of the so-called base isolation meant to decouple the superstructure from the ground, thus modifying the structure’s fundamental period and mitigating damage to structural and non-structural elements. Many insightful models have contributed to a better understanding of the lead core rubber bearings response considered as a separate unit or components of a seismically protected structure. However, the available models can still be enhanced. Furthermore, prediction of the dynamic structural response always offers, in most cases, unique problems; the incorporated models of the devices for seismic isolation play a crucial role in such a context. The article discusses an approach to predict the lead core rubber bearing response considered as a separate unit. To this end, the needed constitutive relations are defined on the material scale. The behavior of the isolator is then studied by transient finite element analysis. Both ready-to-use material models and original procedures (being developed) are considered. Additionally, some features of a data-driven algorithm designed to predict the response of a lead core rubber bearing are outlined.
A methodology for optimizing rod systems is proposed, taking into account the criterion of mechanical safety in the event of emergency actions. Based on evolutionary modeling, an iterative procedure for finding the optimal parameters of structures that have a minimum cost at the maximum level of mechanical safety is con-structed. As such a level of safety, it is proposed to use the value of the ratio of the cost of material damage to the cost of the structure and the condition of resistance to progressive destruction. The search for optimal solutions obtained using the proposed methodology can significantly reduce the consequences of accidents in construction, which can be caused by both natural and man-made fac-tors. The use of this optimization approach has prospects for use both for newly designed load-bearing bar structures and for operating systems with local damage.
Losing heat additionally results in greater energy expenses and waste of resources. In any construction building, the façades ensure the heat transfer between the exterior and the interior surfaces of the structure. The thermal transfer of a façade is dominated by conduction. This exchange makes them responsible for guaranteeing thermal comfort to the occupants. Uninsulated outside walls can cause substantial heat loss, particularly during the winter. The heat is able to pass via such façade, leaving it hard to keep the appropriate temperature inside the construction. Furthermore, there is traditional outside insulation that uses isolative boards, which come in a variety of materials. They require a coat of render on top to provide additional protection from the outdoors as well as a beautiful finish. Impermeability and additional costs are the main disadvantages of such systems. In recent façades (rainscreens), the use of ventilated or unventilated cavities influences the thermal resistance. The rainscreen tends to have lower thermal transmittance than the stone façade. The thermal transmittance of the curtain wall depends on the thermal transmittance of the glazing and that of the mullions/transoms including the spacer of the double-glazing, calculated from a 2D analysis, so the total thermal transmittance will be a weighted average value. Surface or interstitial condensation occurs when humid air touches a surface T less than the dew point temperature; it is less likely to occur in a recent façade than in an old one. The aim of this topic is to achieve an energy comparison between two identical resident structures. The first one was provided with an old façade; however, the other house had a recent façade. The obtained results show an important saving of energy of the recent façade (refund in electricity bills), ensures thermal comfort, reduces embodied carbon, and protects the planet, the atmosphere, and the environment.
A circular cross-section tube-concrete columns (CFSTC) samples study under local compression with initial eccentricity was carried out. Interlocking steel elements were placed in the concrete core in order to increase the strength of eccentrically compressed pipe-concrete columns. They were laid in three rows in the space between the freshly laid concrete upper end and the steel pipe inner surface. Moreover, the interlocking elements lower and upper layers were made in the form of partially truncated tetrahedrons, obtained by cutting the cubes with planes passing through their middle edges into two equal parts. A cubes layer was placed between the truncated tetrahedrons layers so that all the elements were in close contact with each other with their faces. The performed experiments confirmed the interlocking structures ability, due to their high rigidity, to more evenly redistribute concentrated loads transmitted through them. It is shown that the rational geometry selection of the structural interlocking elements and the conditions for their interaction with each other can be an effective method for increasing the structures certain sections rigidity. The 3 layers interlocking elements structure use noticeably changed the pipe concrete columns samples deformation and destruction nature, which led to an increase in the studied samples strength by an average of 11%.
The alternative from the normative method for numerical calculating the construction of the lining of the shallow subway tunnel for standard loads are proposed in this issue. The most important drawback of existing regulatory models and calculation methods is the use linear properties of a material. Applying in practice of new materials, new types of reinforcement, including composite materials, require the use of a more advanced approach for calculation and design of newly constructed structures. It is vital when structures is constructed in seismic prone regions, where it is necessary to take into account seismic loads, as well as reserves of the bearing capability of materials. The proposed method is directed to use real loading diagrams of concrete and reinforcement steel specifications. This approach also allows us to trace the deformation’s character of a reinforced concrete structure in each site of it. By applying proposed below approach a more detailed analysis of the stress and strain state of various elements of the structure are shown here.
In order to study the influence of external packed walls on the seismic performance of prefabricated shear walls, a 1:3 scale prefabricated shear wall specimen with two layers of prefabricated (PC) packed walls was designed and manufactured. The deformation form, maximum floor acceleration, maximum relative floor displacement and interfloor displacement Angle of shear wall structure under different seismic intensities were obtained by shaking table test, and the mechanical performance of the specimen was further studied by finite element simulation method. The results show that the prefabricated filled wall set in Y direction provides a certain lateral stiffness to the shear wall structure and reduces the structural deformation in this direction. It is suggested to consider its influence on the overall stiffness of the structure in the design of the structure. The wall cracks are mainly distributed in the parts of connecting beams, the corners of door and window openings and the parts of wall limbs, and eventually the bearing capacity is lost due to the concrete fracturing in the parts of wall limbs.
Based on the first phase foundation pit engineering of a ship lock, the excavation deformation of foundation pit under the condition of precipitation was studied. Taking cutoff wall as the research object, MIDAS numerical simulation is used to study the influence of the cutoff wall on soil deformation around foundation pit at different depths. The results show that: under the condition of precipitation, the soil around the foundation pit is subjected to the upward frictional resistance of the cut-off wall, and the soil settlement decreases with the increase of the depth of the cut-off wall, and decreases with the increase of the distance from the cut-off wall. Small, the mainly affected area of the soil is 1 to 2 times the excavation depth; the soil at the bottom of the foundation pit produces elastic uplift deformation, which is mainly affected by the penetration of water flow and less affected by the depth of the seepage wall.
Pile-side grouting is the main method to enhance the bearing capacity of in-service pile foundation, the formation parameters have complicated influence on the grouting reinforcement effect. For the problem of inadequate bearing capacity of friction piles in service in alluvial river plains, the effect of the parameters of the complex strata of silty clay and fine sand on the bearing capacity of friction piles reinforced by extrusion grouting was investigated by model tests. When the thickness ratio of powdered clay and fine sand stratum changes from 1:3 to 3:1, the proportion of powdered clay in the stratum increases, and the bearing capacity of the pile foundation decreases by about 50∼100 N. The internal friction angle of fine sand is larger with the particle size increase, and the load transfer efficiency is higher, so the effect of pile side compaction grouting reinforcement is more pronounced. Meanwhile, the water content of powdered clay plays a negative role in the impact of pile foundation grouting reinforcement.
The shale hydration disturbance causes varying degrees of damage to the pore structure of surrounding rock of the borehole wall, deteriorates its mechanical properties, and reduces the safety and stability of the borehole wall. By using nuclear magnetic resonance (NMR) and triaxial compression test, the volume change and mechanical properties of rock samples versus different soaking time were tested and analyzed. Research results: (1) Through the increasing trend of signal intensity amplitude of T2 energy spectrum, the transformation and expansion rules of pores with different scales are analyzed, the mechanical mechanism of shale hydration damage and failure is revealed, and the change rules of shale void ratio and volume expansion rate are analyzed. (2) Through the curves of shear strength and elastic modulus of shale changing with soaking time, the evolution law of shale strength decline is analyzed, which revealed that shale hydration has obvious timeliness. (3) Based on the test results of shale hydration disturbance damage, using damage mechanics and strength statistics theory, and taking the volume expansion rate as the investigation variable, a statistical damage model of shale hydration disturbance is established to predict damage evolution law of shale hydration disturbance. The research results have important guiding significance for practical engineering.
The embedded channel technology avoids the phenomenon of structural damage caused by drilling, making it not only quick and convenient to install, inexpensive overall, simple to maintain, and construction time-saving. As a result, in recent years, China’s underground rail transit has seen a gradual maturation and wide application of construction technology. The embedded channel, which is a novel form of construction, is likely to experience fatigue fractures during the operation of rail transit owing to repetitive loading, which would cause structural collapse. Therefore, it is crucial to research its fatigue characteristics. At the moment, more research on the mechanical characteristics of embedded channel has been conducted both at home and abroad, but there are still few studies on the fatigue properties of embedded channel. As a result, the 30/20 embedded channel bare components are used as the study object in this work, and they are endurance tested. The results of the tests reveal that the specimen fatigue number exceeds 1.2 million times, which meets the standard of 100 years of service life. The study’s findings can serve as a guide for using embedded channel in urban rail transit.
Leakage issues, as a key concern for the quality of underground works, have been influencing construction decisions in engineering practice. Most projects still count leakage on site after a leakage problem has occurred and use this to develop a plugging plan, and as leakage is usually assessed after the overall closure, this leads to insufficient attention being paid to leakage in the preliminary work. In this paper, we take the pursuit of economic benefits as the core and safety and quality as the bottom line for the waterproofing project of the concealed channel of the Ecological Centre project. Before construction, we combine the geological and hydrological situation of the site, conduct statistical analysis of the possible leakage risks and finally focus the waterproofing project on the prevention and treatment of deformation joints, construction joints and concrete cracks. Design from the aspects of waterproof structure design, raw material selection, construction personnel capacity, on-site construction process, etc., to reduce the risk of leakage of underground passages and ensure the normal use of underground passages.
To quantitively analyze the method and effect of shield-embedded channel optimization, establishing a graphic and parameter system based on standardized layout of shield tunnel sections. A mathematical model of optimizing embedded channels and accurate Calculation Formula for Channel Optimization under Common Point Location Conditions was achieved by quantitatively analyzing the optimizable range of standard segments at points 1, 15, 3 and 13 commonly used in straight tunnel sections based on an actual project and construction experiences. By testing in the Hangzhou-Shaoxing Intercity Railway Project, make use of the mathematical model of optimizing embedded channels ,a theoretical optimization rate of 44% for both two-point groups was calculated, which has practical application value for actual projects. The mathematical model of shield construction points and channel optimization for each segment provides a theoretical basis for the shield-embedded channel production, transportation and installation of channel-optimized segments, and can be a reference for other similar studies.
Dynamic failure of brittle rock controlled by complex tensile and shear loads has been a hot topic in both research and practice field. Based on plasticity and damage theory of continuum mechanics, a new Elastoplastic Damage Model (EDM) combining compressive/tensile and shear failure modes together for brittle rock materials is proposed in this study. The EDM is further explicitly solved by Finite Difference Method (FDM) and implemented into FLAC3D commercial software to simulate rock problems. One of application problems of rock mechanics is analysis of the stability of large section tunnels. Ganggou Tunnel is a typical super-large section tunnel with the cross area up to 219.78 m2. The stability of Ganggou Tunnel during excavation process has become a hot issue. Considering the geological condition of Ganggou Tunnel, sets of numerical cases of tunnel excavation with variable net distances between tunnels are carried out. Numerical result such as the distribution law of plastic failure zone, displacement deformation and stress evolution in surrounding rock are analysed. Results indicate that plastic failure zone of surrounding rock increases as net distance between tunnels decreases. While both eventual displacement deformation and tensile stress after tunnel excavation decrease as net distance increases. The new model is validated by well describing the transitional mechanism of tensile and shear modes for rock dynamic problems. The proposed model will provide an effective numerical tool for studying the stability of rock in similar tunnel projects.
Fissure distribution has a significant effect on mechanical properties and damage failure of layered rock mass with complex fissures. Based on the uniaxial compression test and the Digital Image Correlation (DIC) technique, influence of fissure location and fissure angle on the mechanical properties and failure of composite fissure rock sample composed of sandstone-like and martial-like rocks was analyzed. Results show that: (1) Composite fissure rock samples mechanical properties increase with the change of fissure location from sandstone, interface and marble and the increase of fissure angle. (2) When fissure is in marble, initial crack is easy to be far-field crack in sandstone, and surface spalling occurs in both sandstone and marble, but failure is more obvious in sandstone, prone to “H-shaped failure”. When fissure is at interface and sandstone, it is easy to produce wing crack and anti-wing crack at fissure tip of sandstone, “1γ shape failure” and “Y shape failure” are easy to occur respectively. At the same time, stress-strain levels “σ” and “ε” corresponding to initial crack generation at same fissure angle increase with the change of fissure position from sandstone, sandstone to marble and marble. (3) When the fissure location is same, the “σ” and “ε” of α = 90° are the largest, while the “σ” and “ε” of α = 0° and α = 45° are the smallest. “H-shaped failure” occurs when α = 0° and “Y-shaped failure” occurs when α = 90°.
The foundation pit supporting design in deep soft soil sites is often affected by unbalanced soil pressure, so it is necessary to take appropriate supporting measures to ensure the safety of construction. Based on the deep foundation pit project of a riverfront section in the Nansha District of Guangzhou, this paper studies the optimization of deep foundation pit support design under the condition of unbalanced soil pressure in a deep soft soil site. The project is located in an area of deep soft soil, with one side facing the road and the other facing the river. Through the comprehensive analysis of the site engineering and hydrogeology and other aspects, carried out the deep foundation pit supporting structure optimization research, and compared with the three-dimensional numerical simulation results and field monitoring data. Finally, a supporting structure system combining long and short piles with supports or large-diameter anchor cables is selected to coordinate the deformation caused by the unbalance of earth pressure on the riverfront side of the foundation pit. The comparison and analysis of the monitoring data and calculation results show that the selection of the support scheme is reasonable, can meet the safety requirements of the foundation pit and surrounding environment, and has economic performance.
The technique of progressive limiting state of the structure, which is implemented in the form of the displacement method, is considered. The existing formulations of the problems in structural mechanics are based on the principle of the minimum of the total energy of deformation of structures (Lagrange approach), according to which the resulting project corresponds to a predetermined load. But using this approach, it was not possible to obtain information about its residual load-bearing capacity in a deterministic form. To overcome these difficulties, it is proposed to use the criterion of critical levels of deformation energy. The equations of state of the structure at critical energy levels are derived from the variational principle of the minimum of the potential energy of deformation at the critical energy level. The problem is formulated as an eigenvalue problem and the values of the maximum values of the design parameters are found for the stiffness matrix. It becomes possible to calculate the displacements for the critical energy level, and the maximum possible value of the deformation energy of the structure. Subtracting the magnitude of the work of external forces, we obtain the value of the residual potential energy, which determines the residual load-bearing capacity of the structure. When analyzing internal forces in a structure in a critical condition, we determine their greatest values, which cause the limiting state. We call these elements the ‘weak link’ because they will be the first to stop working on an external load. Sequentially removing these elements from the design scheme, we obtain new states of self-tension of the structure until it becomes an unstable system. Thus, we obtain the technique of progressive limiting state of the structure.
The design of a multi-storied steel building requires a lateral load resisting system in addition to the gravity load system, as these are the governing factors in the design and affect its service-life performance. This study aims to demonstrate the impact of several bracing systems in multi-storied steel buildings. Since most multistorey structures comprise reinforced concrete (RC) frame construction, ensuring the design is safe against lateral loads is essential. Steel bracing is mainly used to resist these lateral loads in designing a tall building. Due to its high rigidity, strength, and lateral load-resisting capacity, steel bracing is an excellent alternative for providing lateral support in a high-rise building. The bracing element in a structural design offers additional rigidity, which helps the structure resist earthquake forces. Because of its ease of manufacture and low cost, concentric bracing is one of the most used lateral load-resisting measures in building frames. This study presents the analysis results of various types of bracing (X-bracing, V-bracing, K-bracing and Diagonal bracing) in a structural system using STAAD Pro software and a comparison is presented in terms of maximum lateral displacement, shear forces and bending moments observed due to the application of lateral loads. Tall buildings having 34 storeys with different bracing patterns were analyzed. This study concludes that using bracing units in a structural design significantly alters and improves the structural response of a high-rise building under seismic and wind loads.
Based on experimental studies, a change in the characteristics of the developed concrete composition over time has been established. To determine the parameters of constructing underground structures in ground massifs, a set of studies was performed to assess the stress-strain state of the support at various periods of hardening of fast-hardening monolithic concrete. Modeling with the help of finite element method (FEM) in the software package “Lira-CAD” was carried out, the main factors determining the stress-strain states of the rock mass and supports of the underground structures were determined. As a result of volumetric modeling, the zones of formation of maximum stresses are established and their values are determined. According to the results of calculations of the experimental plan, the partial dependences of the influence of controlled factors on the maximum normal voltages are approximated. Statistical processing of the results using rational methods of planning the computational experiment was used to compile regression models for calculating stresses in the work support and selecting the parameters of carrying out and fastening. A regression model is given for calculating the maximum stresses in the workings support and selecting the parameters of conducting and fastening.
Reinforced soil is widely used in the field of civil engineering and there is a significant difference in performance and mechanism between small spacing reinforced soil (Geosynthetics reinforced soil) and mechanically stabilized soil. Based on the particle flow theory, a simplified model of small spacing reinforced soil structure is established, and the soil arch formation mechanism of fillers of reinforced soil and the influence of spacing between reinforcement materials is analyzed. Research results show that under small spacing conditions, due to the constraint effect of reinforcement materials, the soil near the panel forms a soil arch; When the spacing between reinforcement materials is too large, a stable soil arch cannot be formed. Because of the influence of soil arch, the lateral static earth pressure of the soil filler on the panel decreases with the decrease of the spacing between reinforcement materials and zero lateral static earth pressure can be obtained when the soil arch of the small spacing reinforced soil forms.
Taking a super high-rise building as an example, this paper analyzes the determination principles of pile diameter and pile length, characteristic value of vertical compressive bearing capacity of a single pile, and pile arrangement scheme of non-end-bearing piled raft foundation under the core tube. The quick estimation method of pile number under the core tube, and characteristic value of vertical compressive bearing capacity of a single pile is presented at the stage of pile foundation scheme design. Four pile foundation schemes with different pile diameters and different forms of pile arrangement are analyzed and verified by finite element method, and the results show that the quick estimation method is feasible. At the same time, based on the above analysis and optimized design of pile foundation stiffness to reduce differential settlement of pile foundation, the design optimization strategy of reducing the raft thickness and reinforcement under the core tube is put forward.
PHC piles have become one of the widely used foundation treatment methods in soft soil foundations, but there is little research on the reliability based on the load-displacement curve of uplift piles. The probability regression parameter method can be used to fit the loading section of the PHC uplift load-displacement curve using two parameter exponential functions, hyperbolic functions, and power functions, with goodness of fit greater than 0.98; The unloading section can be fitted using linear and power functions, with goodness of fit greater than 0.85 and 0.94, respectively. The reliability analysis of uplift PHC bearing capacity based on power function fitting function shows: (1) The safety factor and reliability index increase with the increase of allowable displacement; (2) When the safety factor is constant, the variability of parameter aLP in the power function fitting function has the greatest impact, followed by the variability of load, the impact of the variability of fitting parameter bLP on the reliability index can be ignored.
Pipeline integration ALC partition wall, prefabricated pipeline and wire box in the retaining wall, directly saving the construction technology of slotting, burying pipe, repairing and blocking. The construction of the same floor is the ALC wall panel in the main structure construction stage, in the downstairs pre-assembly into a whole wall panel, the development of new wall panel fixtures, lifting AIDS, such as lifting tools, with the realization of the integrated lifting process after pre-assembly. Combined with the actual construction schedule, this paper innovatively adopts the same floor construction method as the main body, analyzes the traditional construction scheme and the same floor construction scheme technology and construction period respectively, and then uses AHP method to calculate the influence degree of the factors influencing the construction period of the two schemes. The research results show that the ALC partition wall adopts the same floor construction scheme, which saves the construction time of the secondary structure, and has a natural advantage over the traditional scheme in terms of saving processes, which can effectively reduce the management pressure and reduce the influence of additional factors on the total construction period.